HS10.1 | General ecohydrology
EDI
General ecohydrology
Convener: Sara BonettiECSECS | Co-conveners: Julian Klaus, Christoph Hinz, Wei Liu, Qi Feng, Chengqi ZhangECSECS, Meng ZhuECSECS
Orals
| Fri, 19 Apr, 10:45–12:30 (CEST)
 
Room 2.15
Posters on site
| Attendance Fri, 19 Apr, 16:15–18:00 (CEST) | Display Fri, 19 Apr, 14:00–18:00
 
Hall A
Posters virtual
| Attendance Fri, 19 Apr, 14:00–15:45 (CEST) | Display Fri, 19 Apr, 08:30–18:00
 
vHall A
Orals |
Fri, 10:45
Fri, 16:15
Fri, 14:00
Ecohydrology, i.e., the study of the interactions between water and ecosystems, is expanding rapidly as a field of research, beyond traditional discipline boundaries in terms of questions and approaches. This session aims to draw examples from this wide field, portraying the current diversity and common features of research frontiers in ecohydrological studies, as well as the range of methods employed. We thus encourage contributions showing novel results or methods when tackling questions related to the coupling of ecological, biogeochemical and hydrological processes, at scales ranging from the single organ or organisms to whole ecosystem/catchment. Contributions relative to all terrestrial and aquatic systems are welcome, including those relative to managed ecosystems, showing how human intervention alters the interactions between water and ecosystems.

Orals: Fri, 19 Apr | Room 2.15

Chairpersons: Sara Bonetti, Christoph Hinz, Meng Zhu
10:45–10:50
10:50–11:00
|
EGU24-4112
|
ECS
|
On-site presentation
Yuanhang Yang, Jiabo Yin, Louise Slater, and Pan Liu

Terrestrial water storage (TWS) is a crucial component in regulating global water and energy budgets, exerting significant impacts on the ecosystem carbon cycle. However, the physical mechanisms behind changes in TWS and its causal relationship with terrestrial carbon uptake remain elusive. Here, we explore water-heat-carbon dynamics using a convergent cross mapping method based on eddy-covariance flux measurements. Then, we employ a supervised machine learning model and path analysis to evaluate the effects of drying TWS on vegetation photosynthesis and respiration. Finally, we project future TWS and drought conditions as well as their impacts on ecosystem vegetation productivity at the global scale. We find that temperature, soil moisture, and radiation are dominant factors regulating carbon update. In most regions of the globe, soil moisture influences vegetation photosynthesis, while the Leaf area index (LAI) plays a dominant role in humid and hyper-dry regions. Our cascade model chain projects that future drought events may have severe negative impacts on vegetation productivity. Terrestrial productivity is projected to be constrained over a growing proportion of global land surface, from the historical period (65.36%) to SSP126 (68.5%), SSP370 (67.4%) and SSP585 (70.67%). As drought severity escalates from moderate to severe, gross primary productivity (GPP) anomalies decrease from -3.53 to -8.4 , suggesting that higher water stress lowers the terrestrial carbon sink. Our results highlight the urgency of enhancing ecosystem resilience to increasingly severe drought conditions.

How to cite: Yang, Y., Yin, J., Slater, L., and Liu, P.: Drivers and effects of drying terrestrial water storage on ecosystem carbon uptake, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4112, https://doi.org/10.5194/egusphere-egu24-4112, 2024.

11:00–11:10
|
EGU24-17131
|
ECS
|
On-site presentation
Fuxiao Jiang, Simone Fatichi, Gianalberto Losapio, and Nadav Peleg

Mountain regions, and the European Alps in particular, are warming faster than other land areas or the global average. The Alps are among the most sensitive terrestrial systems and have rapid and substantial responses to climate change. Consequently, the carbon cycle in high Alpine regions is expected to be significantly impacted by changes in vegetation cover and dynamics. Only a few studies offer insights into how vegetation types and carbon dynamics evolve at high elevation, considering changes in climate and soil conditions. We investigated changes in climate and soil nutrient development due to changes in vegetation type and cover amount using an ecohydrological model (T&C) and focused on the impacts of the changes on the carbon cycle in the Swiss Alps, where extensive glacier retreat is expected. Specifically, we used the Advanced Weather GENerator (AWE-GEN) model to simulate future realizations of climate at the hourly scale with ten RCM realizations under both low (RCP 4.5) and high (RCP 8.5) greenhouse gas emission scenarios. These future realizations drove the T&C model which reproduces all essential components of the hydrological cycle, vegetation dynamics, and soil biogeochemistry to simulate the carbon cycle dynamics over the 21st century. Our study will examine whether the increase in vegetation in glacier forefields is shifting the carbon cycle (e.g., from the carbon sources to carbon sinks). We will present the results of numerical modeling and discuss whether vegetation growth might be restricted despite increased warming by soil nutrient limitations, thereby reducing the rate of CO2 uptake. This study highlights the impact of soil nutrients on vegetation pattern changes and terrestrial carbon cycle dynamics in high-elevation environments.

How to cite: Jiang, F., Fatichi, S., Losapio, G., and Peleg, N.: The role of soil nutrient limitations on terrestrial carbon cycle in the Swiss Alps under climate change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17131, https://doi.org/10.5194/egusphere-egu24-17131, 2024.

11:10–11:20
|
EGU24-10150
|
On-site presentation
Linshan Yang, Xiaohu Wen, Zhenliang Yin, Tingting Ning, and Tuo Han

The remarkable climate change has profound impact on the alpine hydrology, it remains unclear to date on the role of the changes in glacier and frozen ground degradation to the regional streamflow variation. Here, we incorporated the glacier mass balance and frozen ground degradation into the Budyko framework and used the elasticity method to attribute the variation of annual streamflow for 22 rivers in Qilian Mountains (QLM) from 1982 to 2015. The results indicates the simulated annual streamflow that considering glacier mass balance and frozen ground can explain more than 90% of observed streamflow at a significance of p < 0.01, especially for the rivers with high glacier coverage. The elasticity method revealed the simulated streamflow variation can explain more than 91% of variation in respect to the detected streamflow variation. It indicates the robust of the elasticity method and highlights the ability of capture the variation in streamflow with the Budyko framework that incorporated glacier mass balance and frozen ground. There were 3 classifications was clustered and the contribution of precipitation to streamflow variation in the 3 classifications were consistency to the streamflow variation in the 22 rivers of QLM. The precipitation play as a dominant role for the streamflow increased rivers, and ET0 play as a dominant role for the streamflow decreased rivers in QLM. The impact of vegetation on streamflow variation illustrated the strong regional divergence with the contribution varied between -34.55% and 36.79%. The contribution of glacier and frozen ground degradation on streamflow variation were moderate with negative contributions of frozen ground degradation to the streamflow decrease varying between -31.09% and -0.43%, while the contribution of glacier mass balance to variation in streamflow varied between -2.42% and 11.63% in QLM. The results can utilize for understanding the impacts of climate change on alpine hydrological processes and provide the perspective of water resource management.

How to cite: Yang, L., Wen, X., Yin, Z., Ning, T., and Han, T.: Attributing the streamflow variation by incorporating glacier mass balance and frozen ground into the Budyko framework in alpine rivers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10150, https://doi.org/10.5194/egusphere-egu24-10150, 2024.

11:20–11:30
|
EGU24-11298
|
ECS
|
On-site presentation
Sharon Clevers, Camiel Aggenbach, Ruud Bartholomeus, and Jelmer Nijp

Ecohydrological modelling to assist decision making for land- and water management: applications from The Netherlands

Biodiversity in nature areas is severely declining on both global and European levels. Many species and ecosystems are threatened by climate change, desiccation due to lowering groundwater levels and high nitrogen deposition. The Natura 2000 Network, a European-wide network of nature conservation areas, has been created to preserve and restore biodiversity. Ecohydrological processes are a key factor in the conservation of vegetation in nature areas. The relative impact of hydrological measures on biodiversity and vulnerable species is poorly understood in these nature areas, especially when uncertainty associated with climate change is taken into account. This knowledge gap delays decision making for land and water management. This study demonstrates a ecohydrological modelling approach to quantify the impact of hydrological changes on  vegetation.

In recent years, research has been done at KWR Water Research Institute in collaboration with several partners [1] to construct ecohydrological models that include the process-based relationships between water-related habitat factors and vegetation types. These models are currently applied at various spatial scales (local to national) to support decision making. The Water Vision Nature (WWN, in Dutch: Waterwijzer Natuur) is a tool including the model PROBE (PRObability-Based Ecological target model) to simulate the impact of water management, climate change and nitrogen deposition on terrestrial vegetation. PROBE uses the waterlevel output of a groundwater model to calculate the important habitat factors oxygen and transpiration stresses of the vegetation. Additionally, the habitat factors nutrient availability and acidity are derived from output of the hydroloigical model and soil factors. Next, these values are translated into vegetation indicator values for moisture, nutrients and acidity, respectively, by using empirical relationships. PROBE uses these values to predict the occurrence of vegetation types and the botanical nature value of these vegetation types.

To analyse the potential impact of the ecohydrological outlined approach on decision making in land and water management, WWN has been applied to evaluate local restoration and management plans of Natura 2000 areas in the Netherlands. These studies show that the process-based ecohydrological model PROBE is a useful method to analyse future management scenarios in nature areas by taking into account both water management measures and climate change scenarios.

[1] Wageningen University en Research , Stowa, Nutrient Management Institute (NMI) and Hoefsloot Spatial Solutions (HSS)

How to cite: Clevers, S., Aggenbach, C., Bartholomeus, R., and Nijp, J.: Ecohydrological modelling to assist decision making for land- and water management: applications from The Netherlands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11298, https://doi.org/10.5194/egusphere-egu24-11298, 2024.

11:30–11:40
|
EGU24-11709
|
ECS
|
On-site presentation
Gökben Demir, Ruth-Kristina Magh, Janett Filipzik, Viktor Schreier, Johanna Clara Metzger, Beate Michalzik, and Anke Hildebrandt

Vegetation relies on soil water to meet transpiration demands. Furthermore, the canopy intercepts precipitation and introduces spatial heterogeneity in water entering the soil not only in forests but also in grasslands. Some studies showed that in mixed forests, trees tap water from deeper layers in response to long dry spells to compensate transpiration demands. In contrast, recent observations indicate that water uptake from deeper layers is almost negligible, which may be the main reason for the drought susceptibility of many forests in Central Europe. Moreover, canopy induced variability in precipitation distribution at the ground could influence water uptake patterns, which is rarely considered in forests and not investigated in grasslands. Therefore, we examined root water uptake and soil water patterns considering the impact of canopy-driven heterogeneity in subsurface processes through field observations. The research site consists of a mixed deciduous forest (1 ha) and an adjacent grassland (0.045 ha) site in Hainich Critical Zone Observatory, Thuringia, Germany. The forest site is dominated by European beech and hosts other species such as sycamore maple, European ash, while the plant community in the grassland is characterized by different functional plant groups such as graminoids, legumes and herbs. Both sites were equipped with closely paired (within 1 m) throughfall and soil moisture measurements (nforest = 34, ngrassland = 22). We sampled throughfall weekly at both sites in 2019 (March-August) and 2022 (May-September) along with gross precipitation and grass height measurements. At both sites, we derived root water uptake from diurnal fluctuations in soil water content at two depths during rain-free periods.

The growing season in 2022 was drier than in 2019 (Pgross, cum,2019 < 200 mm), resulting in less than 100 mm of cumulative gross precipitation within the sampling period. In addition, dry spells were longer and more frequent in the 2022 growing season. At the forest site, the topsoil layer held more water than the deeper layer throughout the sampling period in 2019 and early in the season 2022. In the grassland plot, the topsoil layer stored precedingly less water in both years through the growing season, especially after summer mowing, which is probably due to preferential flow. In the forest, the average water uptake depth systematically shifted to deeper layers in the dry growing season of 2022, so that after mid-July roots mostly tapped water from deeper layers. In 2019, the relatively wetter growing season, changes in uptake depths were also related to tree size. The average daily transpiration reached 3 mm in 2019 while it decreased to less than 2.5 mm in 2022 despite the higher evapotranspiration demand, indicating a strong drought effect. In the grassland plot, in both years, the deeper soil layer facilitated higher water uptake over the growing season in line with grass development and remained so even after summer mowing. Our results suggest that severe droughts can alter water uptake strategies in mixed species forest and grassland sites.

How to cite: Demir, G., Magh, R.-K., Filipzik, J., Schreier, V., Metzger, J. C., Michalzik, B., and Hildebrandt, A.: Spatio temporal variation of root water uptake in a mixed deciduous forest and a grassland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11709, https://doi.org/10.5194/egusphere-egu24-11709, 2024.

11:40–11:50
|
EGU24-19109
|
ECS
|
On-site presentation
|
Concetta D'Amato and Riccardo Rigon

This contribution aims to present a concise and effective methodology for accurately characterizing transpiration, a crucial component of the hydrological cycle. Rather than delving into intricate derivations of transpiration formulas, we employ simplifications, such as a century-old turbulence model, principles from Lord Kelvin's thermodynamics, and an energy budget overlooking thermal leaf capacity. Despite these simplifications, we assert the general validity of our approach in identifying primary mechanisms underlying transpiration.

Our methodology initiates with a treatment of five equations, including the mass budget, outlining the procedure: Clausius-Clapeyron equation, water vapor transport, turbulence-induced thermal energy transport, and stationary energy budget with radiative feedback. Initially, we introduce a simplified approach excluding the water budget, followed by its inclusion to demonstrate that adhering to the water budget is sufficient without imposing artificial constraints. Utilizing a linearized form of the Clausius-Clapeyron equation, we establish the Penman Formula, a well-regarded solution for estimating temperature (T), air vapor content (e), and thermal heat transport (H). Through water mass balance, we reveal that leaf pressure potential is dynamically influenced by atmospheric evaporation demand and soil moisture content, challenging the notion of capillarity as the sole determinant. Building on Schymanski and Or's (2017) research, we extend it by explicitly incorporating the canopy. Even within the "big leaf" approach (Bonan et al., 2021), we introduce a dependency on leaf area index (Lc) in formulas to accurately consider the canopy's impact. Additionally, we provide a detailed treatment of radiation, accounting for the canopy's influence, following Ryu et al. (2011) and de Pury (1995) methodologies.

In the realm of canopy analysis, our contribution reveals discrepancies compared to common simplistic approaches, shedding light on unique aspects of the subject matter.

How to cite: D'Amato, C. and Rigon, R.: Elementary mathematics sheds light on the transpiration budget, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19109, https://doi.org/10.5194/egusphere-egu24-19109, 2024.

11:50–12:00
|
EGU24-19296
|
On-site presentation
Nicola Montaldo and Roberto Corona

Dryland ecosystems are widely spread all around the world, and are characterized by their sensitivity to meteorological seasonal and decadal changes, which impacts water availability and ecosystem sustainability. For instance, in Mediterranean dryland ecosystems climate change occurred with an increase of air temperature and a decrease (mainly in wet seasons) of precipitation, which are key atmospheric forcing for grass and tree growths. Climate predictions of future scenarios of the Intergovernmental Panel on Climate Change (IPCC) are even worse, affecting, for instance, the central Mediterranean basin with a further decrease of rainfall in wet months and an increase of air temperature. The case study is a typical Mediterranean ecosystem in Sardinia, where wild olives and seasonal grass species grow on thin surface soil layer overlaying a fractured rock sublayer, and for which a long-term dataset of micrometeorological, tree transpiration, remote sensing data and soil water content measurements is available. Our objectives are: 1) detect trends and changes on the evolution of tree cover spatial distribution related to changes on climate conditions, and investigate the impact on soil water and evapotranspiration using a long ecohydrological database of a typical water-limited ecosystem; 2) develop an ecohydrological model for long-term predictions able to capture the evolution of tree cover spatial distribution, vegetation dynamics, and soil water balance interactions; 3) investigate the impact of future climate scenarios with increase of CO2 on soil water balance and tree hydrological sustainability of a Mediterranean dryland ecosystem. The Sardinian field site is characterized by a very attractive long database of almost 60 years of data, with micrometeorological and meteorological measurements, remote sensing data and aerial photography images, providing a unique opportunity to analyze the response of the tree-grass ecosystem to the historical climate and land cover changes. The proposed model was able to reproduce well the soil, vegetation and atmosphere interactions and dynamics, and their long-term evolution. The proposed update of the model was accurate for predicting the long-term dynamics of the tree cover fraction evolution, which have been reduced drastically (0.10) by a human induced fire almost 60 years ago, and restored naturally in almost 20 years, reaching the equilibrium value (0.33). The Sardinian tree-grass ecosystem suffered an historically significant reduction of the rain and a significant increase of air temperature in the last century, which produced dryer conditions but with a recent mean annual precipitation (MAP) still above 600 mm, apparently enough for sustain the tree growth. The GCM future scenarios are even worse, predicting a further decrease of MAP up to 400 mm, and an increase of air temperature up to +10 °C, which will cause a reduction of the tree cover fraction up to 0.10, and a strong decrease of the tree LAI. The soil water balance is predicted being drier, with also less grass and vegetation in general, with consequences on the landscape aspect, becoming more and more a savanna-like ecosystem. Water resources and environmental planning strategies need to be consider for increasing the resilience of the tree-grass ecosystems to the climate changes.

How to cite: Montaldo, N. and Corona, R.: Hydrologic Sustainability of a Dryland Tree-Grass Ecosystem in the Mediterranean Region Under Climate Change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19296, https://doi.org/10.5194/egusphere-egu24-19296, 2024.

12:00–12:10
|
EGU24-1517
|
On-site presentation
Xinping Wang

A major concern for revegetated desert ecosystem is accounting for the evapotranspiration dynamics which is influenced by the carrying capacity of the soil moisture content. Most field observations indicate that soil moisture at certain depth varies with the stochastically occurrence of rainfall events, and the evapotranspiration at community level also varies with the total of annual precipitation. Based on a study of the long-term field observation on the revegetated desert ecosystem, we find that the evapotranspiration of the shrub community correlates closely to the availability of soil moisture, and it can be quantified by analytical description of the stationary and transient joint behavior of plant evapotranspiration and soil moisture. The experimental results indicate that the size and diversity of plant species in water-limited ecosystem can be determined by plant evapotranspiration, which is a comprehensive indicator for plant water resource competition. These results suggest that revegetating large sandy areas with desert shrubs could reduce soil water storage by transpiration, which could significantly change groundwater recharge conditions. However, from a viewpoint of desert ecosystem reconstruction, it appears that natural rainfall can sustain desert shrubs which would reduce erosion loss of sand.

How to cite: Wang, X.: Variation among desert shrub patches in evapotranspiration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1517, https://doi.org/10.5194/egusphere-egu24-1517, 2024.

12:10–12:20
|
EGU24-2069
|
On-site presentation
Ping Wang and Yuyan Liu

Vegetation plays a crucial role in river hydrodynamic processes, and the accurate prediction of vegetation drag force is essential for effective river management and ecosystem protection. The interactions within the vegetation canopy must be quantified to understand their impact on drag force. This study delves into the canopy interaction mechanisms of rigid emergent aquatic vegetation, with a specific focus on blockage and sheltering effects. Through a series of flume experiments, we systematically explored various combinations of lateral and longitudinal spacing, including special single row and single column arrangements. Our experimental design includes various combinations of lateral and longitudinal spacing, as well as special single row and single column arrangements. This allowed us to provide a more precise understanding of how lateral and longitudinal spacing affect the blockage and sheltering effects. Furthermore, we introduced a unified reference velocity that combines two effects, based on which we have established a widely applicable drag model that can predict drag under various density conditions. Additionally, we propose a critical characteristic value for quantifying drag, shedding light on the ultimate performance of drag under different spacing arrangements. These findings offer a reliable framework for predicting drag in rigid emergent vegetation canopies, significantly advancing our comprehension of vegetation's influence on hydrodynamic processes. The established drag model serves as a practical tool for river management and ecosystem protection, providing valuable guidance for sustainable environmental practices.

How to cite: Wang, P. and Liu, Y.: Drag in Vegetation Canopy: Considering Sheltering and Blockage Effects, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2069, https://doi.org/10.5194/egusphere-egu24-2069, 2024.

12:20–12:30
|
EGU24-2234
|
ECS
|
On-site presentation
Zekun Meng and Ping Wang

Flexible submerged vegetation plays a pivotal role in ecosystem. Exploring the relationship between flexible vegetation deformation and flow velocity distribution is essential due to the complex disturbance caused by the bending characteristics of vegetation in water flow. Previous studies have typically relied on constant drag coefficients to predict vertical velocity distribution. However, the broad range of drag coefficient variability in flexible vegetation presents challenges in coefficient selection. In this paper, the developed prediction model of velocity profile based on multi-factor-dependent drag coefficient is derived by cantilever beam theory, dual-layer averaged velocity model and the relationship between the averaged inclination angle and Cauchy number, and the application of this prediction model is highly favorable. Meanwhile, a new analytical expression for depth-averaged drag coefficient of submerged vegetation with deformation angle and Reynolds number is proposed. These equations can reflect the influence of submergence as well. The findings of this study may provide valuable insights into the variability of drag coefficients and the flow structure with submerged flexible vegetation. And it can serve as a foundational basis for the restoration and management of freshwater ecosystems.

How to cite: Meng, Z. and Wang, P.: Velocity profile in steady flow with submerged flexible vegetation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2234, https://doi.org/10.5194/egusphere-egu24-2234, 2024.

Posters on site: Fri, 19 Apr, 16:15–18:00 | Hall A

Display time: Fri, 19 Apr 14:00–Fri, 19 Apr 18:00
Chairpersons: Julian Klaus, Wei Liu, Qi Feng
A.125
|
EGU24-18767
|
ECS
Francesco Alongi, Emilio Badalamenti, Fulvio Capodici, Dario De Caro, Giuseppe Ciraolo, Tommaso La Mantia, Dario Pumo, and Leonardo Valerio Noto

Plant species diversity is fundamental for the stability and resilience of ecosystems, and the well-being of the entire planet. Healthy and diverse ecosystems also contribute to air and water pollution removal, climate regulation and flood prevention. In the last century, plant biodiversity has been facing severe threats, such as habitat destruction and fragmentation due to increasing urbanization, deforestation, agricultural expansion, wildfires, and pollution. In addition, changes in climate pose significant threats to plants biodiversity conservation and native species preservation. All these natural and anthropic disturbance factors are profoundly modifying the competitive dynamics among plant species, often favouring the establishment and spread of some invasive plants, and exacerbating the biodiversity loss of native ecosystems.

A well-known invasive alien species is Ailanthus altissima, a tree native to East Asia and introduced to various regions around the world, including North America and Europe. It is characterized by rapid growth, high reproductive capacity, and ability to thrive in a wide range of environmental conditions, where it can significantly modify ecosystems by altering soil characteristics, releasing allelopathic chemicals that may inhibit the growth of other plants, and forming dense thickets that reduce the space available and development chance of native vegetation. Ailanthus has been recognized as the most widespread and invasive alien tree species in Sicily (Italy), with a capillary presence over the entire regional territory, where it poses a serious threat to the biodiversity of the local Mediterranean ecosystems.

Ecohydrological models can simulate vegetation dynamics and predict Ailanthus encroachment mechanisms also in presence of disturbance effects and under climate change. In this work, the CATGraSS, an ecohydrological Cellular Automata model (Zhou et al., 2013), has been used for simulating spatio-temporal dynamics of Ailanthus altissima in a specific site of “Vallone di Piano della Corte” Nature Reserve, in the Erei mountains in central Sicily (Italy). The study area has a surface of approximately 1 km2 and it is characterized by a relevant nucleus of Ailanthus that has been growing rapidly in recent years. The study aims to reconstruct Ailanthus altissima spatio-temporal evolution in the study area over the last century. The model has been calibrated using the current Ailanthus distribution maps, obtained by classifying high-quality satellite images, collected by PlanetScope constellation, exploiting modern remote sensing techniques, together with field surveys.

How to cite: Alongi, F., Badalamenti, E., Capodici, F., De Caro, D., Ciraolo, G., La Mantia, T., Pumo, D., and Noto, L. V.: Encroachment analysis of the invasive tree species Ailanthus altissima in Sicily (Italy) through an ecohydrological cellular automata model , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18767, https://doi.org/10.5194/egusphere-egu24-18767, 2024.

A.126
|
EGU24-13909
|
ECS
Yexia Lin Xu, Naika Meili, and Simone Fatichi

Urbanisation substantially alters the permeability of the land surface and modifies the vegetation cover extent and type. These landcover changes profoundly affect the hydrological and energy budget. While the role of urbanization on the local flood response has been extensively studied, its effect on the long-term hydrological budget is much less known as computing the latent heat flux (evapotranspiration) in urban areas is still challenging. However, knowledge on the urban hydrological budget is important as many cities are planning water sensitive urban designs and water harvesting could be key to support an increasing amount of urban vegetation.

This study quantifies how urbanization changed the long-term hydrological budget of the island city state Singapore for the period between 1982 to 2021. To do so, we use two state-of-the-art mechanistic models which include all the major hydrological components such as runoff, soil and interception water storage, transpiration, and evaporation. The first is Tethys-Chloris (T&C), which is a mechanistic ecohydrological model that can resolve the water, carbon and energy budgets at high spatio-temporal resolutions but considers the urban effects in a simplistic way by only modifying the impervious fraction of the land surface and its roughness. The second is its urban counterpart, Urban Tethys-Chloris (UT&C), which explicitly resolves shading and radiation reflection within an urban canyon accounting for different urban vegetation types and configurations and explicitly resolves the local urban climate and hydrology. UT&C is however too computationally costly to simulate an entire city at high spatial resolution. Hence, a machine learning approach, where a multimodal neural network comprising a Conv1D layer followed by LSTM layers for dynamic meteorological inputs and Dense layers for static inputs such as urban properties, is used to re-map UT&C outputs over the entire city based on a few selected covariates.

By cross comparing the different approaches to compute the long-term water budget over urban areas, we highlight the involved uncertainties, and we can gain insights into the impact of urban development on modifying the water availability in Singapore. The island city-state relies on water harvesting as one source of water supply for households and knowledge of water availability is extremely important for long-term water management purposes.

How to cite: Lin Xu, Y., Meili, N., and Fatichi, S.: Long-term hydrological budget over urban areas: approaches and challenges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13909, https://doi.org/10.5194/egusphere-egu24-13909, 2024.

A.127
|
EGU24-13181
|
ECS
Meng Zhu, Qi Feng, Wei Liu, Chengqi Zhang, and Jutao Zhang

The underlying surface structure is being reshaped by climate change and human activities, which in turn affects the hydrological processes in inland river basins, with significant consequences for coupling patterns of water and land resources in inland river basins of arid and semi-arid regions. However, current studies of coupling pattern of water and land resources analysis focus on available water and visible land resources in the districts, so that there is an urgent need for research on the simulation and prediction for water and land resources coupling of the micro-scale. Therefore, this study firstly evaluated and predicted the land resources by MCE-CA-Markov model and soil quality index function with environment factors and socio-economic factors, then generalized and simulated the water resources by SWAT, and construct the Water-Land Nexus Model for water conservation and water consumption zones to clear the impact mechanisms of water and land resources nexus in inland river basins. The results show that the nexus index of water and land resources present a decreasing distribution from water conservation area to water consumption area of the Shiyang River Basin, with that being lower than 0.1 (mainly in the water consumption area). The coupling index of water and land resources of Shiyang River Basin decreases from 0.1105 in 1980 to 0.1071 in 2000. In 2020-2050, the water conservation area exhibit an increasing trend, but that of the water consumption area is decreasing. The Geo-detector results show that soil quality index, blue water resource and DEM are the main factors influencing the coupling of water and land resources in Shiyang River Basin, follow by precipitation, temperature and green water resource, and the effects of POP and GDP could be negligible. Furthermore, the interactions between natural and socio-economic factors are stronger than the ones within each other, indicating that natural factors are the main influences on water-land nexus and it is important to consider the interactions of nature along with the human activities.

How to cite: Zhu, M., Feng, Q., Liu, W., Zhang, C., and Zhang, J.: Patterns, controls and predictions of water and land resources nexus in a typical inland river basina: A green-blue water perspective, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13181, https://doi.org/10.5194/egusphere-egu24-13181, 2024.

A.128
|
EGU24-8204
|
ECS
Katarina Zabret, Lana Radulović, Mark Bryan Alivio, Nejc Bezak, and Mojca Šraj

The rainfall erosivity influences the detachment of soil particles, movement and washing away the surface soil layers, which affects soil degradation and leads to various environmental problems. It depends primarily on the kinetic energy of raindrops, determined by the size and velocity of raindrops. However, rainfall microstructure (size, velocity and number of raindrops) is significantly changed during the process of rainfall interception. Precipitation, that is not intercepted by the vegetation, reaches the ground as throughfall (falling directly through the gaps in the canopy or dripping from the leaves and branches) or stemflow (flowing down the branches and stem). Therefore, the kinetic energy of throughfall under the vegetation is different than kinetic energy of open rainfall.

In the urban park located in Ljubljana, Slovenia, we have monitored the rainfall microstructure in the open and underneath the deciduous (Betula pendula Roth.) and coniferous (Pinus nigra Arnold) trees between 12 July 2022 and 19 July 2023. We have analysed the differences between rainfall microstructure and kinetic energy of raindrops in the open and underneath the trees.

The observed average number of raindrops per event under both trees was lower than the number of raindrops in the open. Also, the average kinetic energy of drops per event was significantly lower under the trees than in the open. Additionally, an analysis of factors influencing the kinetic energy of throughfall drops underneath the both trees was performed using the boosted regression trees and random forest models. Both models identified rainfall amount as the most influencing factor.

Acknowledgments: Results are part of the research programme P2-0180 and research projects J2-4489, N2-0313 and J6-4628, financed by the Slovenian Research Agency (ARIS).

How to cite: Zabret, K., Radulović, L., Alivio, M. B., Bezak, N., and Šraj, M.: Factors influencing the kinetic energy of throughfall drops, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8204, https://doi.org/10.5194/egusphere-egu24-8204, 2024.

A.129
|
EGU24-13757
Zhixiang Lu, Qi Feng, and Jiali Xie

The impacts of alternating dry and wet conditions on water production and carbon uptake at different scales remain unclear, which limits the integrated management of water and carbon. We quantified the response of runoff efficiency (RE) and plant water-use efficiency (PWUE) to a typical shift from dry to wet episode of 2003–2014 in Australia's Murray-Darling basin using good and specific data products for local application, including Australian Water Availability Project, Penman-Monteith-Leuning Evapotranspiration V2 product, MODIS MCD12Q1 V6 Land Cover Type and MODIS MOD17A3 V055 GPP product. The results show that there are significant power function relationships between RE and precipitation for basin and all ecosystems, while the PWUE had a negative quadratic correlation with precipitation and satisfied the significance levels of 0.05 for basin and the ecosystems except the grassland and cropland. The shrubs can achieve the best water production and carbon uptake under dry conditions, while the evergreen broadleaf trees and evergreen needleleaf trees can obtain the best water production and carbon uptake in wet conditions, respectively. These findings help integrated basin management for balancing water resource production and climate change mitigation.

How to cite: Lu, Z., Feng, Q., and Xie, J.: Basin management inspiration from impacts of alternating dry and wet conditions on water production and carbon uptake in arid region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13757, https://doi.org/10.5194/egusphere-egu24-13757, 2024.

A.130
|
EGU24-13561
Tengfei Yu, Tuo Han, Haiyang Xi, and Baofeng Li

Knowledge on relationship and determinants of water and carbon dioxide (CO2) exchange is crucial to land managers and policy makers especially for the desertified land restoration. However, it remains highly uncertain in terms of water use and carbon sequestration for artificial plantation in desert. Here, the continuous water and carbon fluxes were measured using eddy covariance (EC) in conjunction with hydrometeorological measurements over an artificial C4 shrub, Haloxylon ammodendron (C. A. Mey.) Bunge, from July 2020 to 2021 in Tengger Desert, China. In the entirely 2021, evapotranspiration (ET) was 189.5 mm, of which 85% (150 mm) occurred during growing season, that was comparable with precipitation (132.2 mm) plus dew (33.5 mm) and potential other sources (e.g. deep subsoil water). This ecosystem was a strong carbon sink with net ecosystem production (NEP) up to 446.4 g C m-2 yr-1, which was much higher than surrounding sites. Gross primary production (GPP, 598.7 g C m-2 yr-1) was comparable with other shrubs but ecosystem respiration (Re, 152.3 g C m-2 yr-1) was lower. Random Forest showed that environmental factors can explain 71.56% and 80.07% variation of GPP and ET, respectively. However, environmental factors have divergent effect on water and carbon exchange, of which soil hydrothermic factors (e. g. soil moisture content and soil temperature) determine the magnitude and seasonal pattern of ET and Re, while aerodynamics factors (e.g., net radiation, atmospheric temperature and wind speed) determine GPP and NEP. As such, divergent response of abiotic factors resulted in the decoupling of water and carbon exchange. Our results suggest that H. ammodendron was a suitable species for large-scale afforestation in desert or desertification-prone region given its low water use but high carbon sequestration. Therefore, we concluded that artificial planting H. ammodendron in dryland could provide an opportunity for climate change mitigation, however, the long-term time series data would be needed to confirm it.

How to cite: Yu, T., Han, T., Xi, H., and Li, B.: Relationship and determinants of water and carbon dioxide (CO2) exchange in desert ecosystem, China , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13561, https://doi.org/10.5194/egusphere-egu24-13561, 2024.

A.131
|
EGU24-4624
Xiaohui Jin

The effects of water on vegetation have always been a concern. It is an important support as well as a major limiting factor with respect to vegetation growth. By analyzing the spatiotemporal changes and correlations between precipitation (PRE), soil moisture (SM), vapor pressure deficit (VPD), and normalized difference vegetation index (NDVI) in the Yellow River Basin, we explored the different effects of different water elements on vegetation. Our findings reveal the following: (1) NDVI and the three water elements report an increasing trend in the Yellow River Basin, with NDVI increasing most significantly. (2) The changes in vegetation are closely related to arid and humid zoning of the Yellow River Basin. NDVI of arid regions is significantly lower than that of humid regions; additionally, NDVI of natural vegetation in arid regions is lower than that of crops planted in irrigation areas, whereas the opposite is true in humid regions. (3) 92.1% of the Yellow River Basin showed an increase in NDVI, and 76.4% showed a significant increase. The proportions with trends of increasing in PRE, SM, and VPD were 75.40%, 51.88%, and 49.71%, with significant increases of 4.5%, 9.5%, 17.9%, respectively; (4) Vegetation in the Yellow River Basin was most positively affected by PRE, followed by SM and VPD. PRE mainly affected the natural vegetation on both sides of the boundary between the arid and semi-arid regions and the semi-humid regions. SM mainly affected the natural vegetation in the arid and semi-arid regions, whereas VPD mainly affected the crops in the irrigation areas, and the irrigation areas in arid regions were affected the most. These findings contribute to a deeper understanding of the relationship between water elements and vegetation, as well as the formulation of strategies for the healthy development of regional natural vegetation and crops in areas of irrigation.

How to cite: Jin, X.: Different effects of Multiple Water Elements on Vegetation: A Case Study of the Yellow River Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4624, https://doi.org/10.5194/egusphere-egu24-4624, 2024.

A.132
|
EGU24-16875
|
ECS
Zaiyong Zhang, Qi Feng, Chengcheng Gong, Meng Zhu, Wei Liu, Jutao Zhang, and Anyuan Li

Artemisia ordosica can prevent desertification and increase carbon sequestration, and it has been extensively planted in the Mu Us Desert, China. Evapotranspiration (ET) plays an important role in the survival of Artemisia ordosica. However, the controlling factors of ET remain unknown. To investigate the influencing factors on the actual evapotranspiration, we set up a weighing lysimeter with Artemisia ordosica in the Mu Us Desert. We collected data of air temperature (Ta), net radiation (Rn), wind speed (WS), soil moisture (θ), vapor pressure deficit (VPD), and heat flux (HF). The multiple linear regression model was used to quantify the influence of the six environmental factors on the ET. In addition, we applied the boosted regression tree (BRT) method to quantify the relative contribution of these environmental factors to ET. Our results show that annual ET was 444.46 mm, which was mainly influenced by the VPD during the dry season and Rn during the rainy season. This is different from the previous results which emphasized the importance of θ and Ta. The BRT results show that VPD and Rn are the most contributors to ET in the research area. In addition, ET significantly decreased when the soil moisture was less than 0.063 cm3/cm3. ET can increase by an average of 90% after a rainfall event. Our results have significance for the hydrological cycle and ecological environment protection.

How to cite: Zhang, Z., Feng, Q., Gong, C., Zhu, M., Liu, W., Zhang, J., and Li, A.: The influence of environmental factors on the actual evapotranspiration of Artemisia ordosica , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16875, https://doi.org/10.5194/egusphere-egu24-16875, 2024.

A.133
|
EGU24-19628
Yueping Xu, Lu Wang, Haiting Gu, and Li Liu

The Yellow River basin (YRB), as a crucial ecological corridor in the northern part of China, has experienced profound changes in multiple eco-hydrological processes. However, there is still lack of a global view on the variations and causal interactions in the complex hydro-ecological system of YRB. In this study, a set of eco-hydrological variables, regarding water resources (surface water, soil water, groundwater) and ecological environment (vegetation growth, productivity, water use efficiency) are used to represent the main characteristics of the eco-hydrological system in different sub-regions of YRB. The objective of this study is three-fold. Firstly, the individual variation of each eco-hydrological variable was unraveled using trend analysis. Secondly, network analysis was used to analyze the synergistic variations among variables. Finally, an advanced causal discovery tool incorporating prior knowledge was used to investigate the potential causal interactions in eco-hydrological system. The results indicate the decrease of terrestrial water storage anomalies (TWSA) in most parts of the YRB, which is mostly due to the substantial depletions in ground water. The vegetation growth and productivity have noticed prominent increasing trends in YRB, and such increase in the source region is largely due to the warmer climate condition and in the middle reaches is mainly because of the large-scale vegetation restoration. However, the ecosystem water use efficiency (WUE) is not very optimistic, especially in the source region. The causal discovery method captures the inhibitory effect of evapotranspiration on WUE in the upper and some parts of the middle reaches of YRB. Our study provides a new perspective to recognize the complicated eco-hydrological conditions and their variations in YRB during 2001-2019, as well as the potential mechanisms driving these variations.

 

How to cite: Xu, Y., Wang, L., Gu, H., and Liu, L.: Variations and causal interactions in the eco-hydrological system of Yellow River basin, China: A Network Perspective, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19628, https://doi.org/10.5194/egusphere-egu24-19628, 2024.

A.134
|
EGU24-19281
|
Siwei Chen, Yueping Xu, and Yuxue Guo

Ecosystem water use efficiency (WUE, defined as the ratio of primary productivity to evapotranspiration) has garnered significant attention in recent years for its role as a vital indicator of the interplay between carbon and water cycles. Numerous studies have underscored the substantial impact of elevated CO2 concentrations on WUE through changes in climate and land surface properties. However, the relative contributions of these factors and their interrelations remain less clear. This study delves into the linkage between WUE and the water-energy exchange dynamics within the Yellow River Basin, employing the Budyko framework model as a foundation. We propose and validate a linear Budyko model tailored to WUE, demonstrating satisfactory physical performance (R2 = 0.60-0.73). Building on this, we construct an attribution framework for WUE, grounded in the Budyko model and global climate models (GCMs), to quantitatively disentangle the impacts of climate and land use change, as well as to elucidate the mechanisms underlying CO2-induced radiative and biogeochemical effects on WUE. Our attribution analysis suggests that the WUE of the Yellow River Basin is anticipated to increase by 0.36-0.84 (g C/kg H2O) in future scenarios, with climate change being the predominant driving force (77.9%-101.4%). The study also uncovers variations in the response of WUE to different drought conditions within the basin. Specifically, we observe an increase in WUE under moderate drought conditions, whereas a decline is noted in most areas as drought severity escalates. Under high emissions scenarios, WUE exhibits a more pronounced sensitivity to drought, particularly under extreme conditions. The outcomes of this research contribute to our understanding of how future CO2 concentration increments, under varying scenarios, may induce changes in WUE in the Yellow River Basin. Moreover, they reveal the prospective response mechanisms of vegetation to drought events within the basin, offering a scientific basis for the formulation of regional ecological strategies and water management practices.

 

How to cite: Chen, S., Xu, Y., and Guo, Y.: Attribution and Response of Water Use Efficiency to Future Changes  in the Yellow River Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19281, https://doi.org/10.5194/egusphere-egu24-19281, 2024.

A.135
|
EGU24-19734
|
ECS
Luisa Coder, Olaf Büttner, Kay Knöller, Pia Marie Kronsbein, Andreas Musollf, and Jörg Tittel

Central Europe has experienced an extreme drought over the last five summers, which has led to a deficit in precipitation and discharge unlikely to be replenished quickly. Due to climate change, extreme weather events and accompanying droughts are likely to occur more frequently in the future putting pressure on aquatic ecosystems. In addition, rivers have been significantly modified over the years, with channelization and the construction of dams drastically altering the natural flow of the river. Floodplains have been cut off and natural habitats have been lost. This underlines the need to investigate the interactions of climate change and antropogenic alterations to rivers and to establish a safe operating space for floodplain areas to ensure their ecological function. To achieve this, we investigated 36 floodplain lakes near the Elbe River in Magdeburg, Germany, with varying connectivity to the main river and different characteristics of each lake. Water samples were taken from the lakes, the main river and the groundwater. Major ions and isotopes to determine the origin of the water. Further, chlorophyll a was sampled and parameters such as oxygen and hydrogen sulfide were taken. Along with recorded fish kills and measured water level, a scoring system was established to determine the degree of impairment and habitat loss of each lake. Connectivity, defined here as the frequency of an existing surface connection of the lake to the main river, was determined to provide a measure of the impact of anthropogenic modification and channelization of the river bed. The difference in deuterium excess between fall and spring served as a measure of evaporation and thus of the influence of climate change during the sampling campaign. Critical chlorophyll a concentrations were measured in surface waters in lakes with less than 50 % connectivity, critical oxygen concentrations in lakes with less than 10 % connectivity. Fish kills, hydrogen sulfide, siltation and dry-out occurred predominantly in lakes with a low connectivity. Finally, lakes with a small perimeter by area were found to exhibit fewer signs of degradation and habitat loss. Our results suggest that lakes that are connected to the main river are better able to respond to drought stress caused by climate change. Therefore, better connectivity to the main river may help to reduce habitat degradation or loss in the floodplain ecosystem.

How to cite: Coder, L., Büttner, O., Knöller, K., Kronsbein, P. M., Musollf, A., and Tittel, J.: How anthropogenic modification of riverscapes reduce the resilience of floodplain waters to drought, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19734, https://doi.org/10.5194/egusphere-egu24-19734, 2024.

A.136
|
EGU24-18264
|
ECS
Francesca Padoan, Giulio Calvani, Giovanni de Cesare, and Paolo Perona

The purpose of this work is to present the results of a literature data re-analysis of HSI and demonstrate the existence of a universal level of similarity in the ranges of hydraulic variables for the considered species.

The decline in biodiversity within freshwater ecosystems is a critical issue influenced by many factors, including the increasing pollution levels and the proliferation of invasive species. Globally, river management strategies have increasingly incorporated river restoration efforts and actions aimed at preserving freshwater species, such as the brown trout (Salmo trutta L.). From a quantitative point of view, the efficiency of proposed restoration measures on river ecomorphology is assessed via the HSI, whose use is widely embraced by aquatic ecologists, river scientists, and engineers. For the specific case of the brown trout, the HSI takes into account several environmental factors, including flow velocity, water depth, and substrate type, which directly represent the environmental characteristics of the habitat. Despite variations in HSI curves based on geographical location and other incidental factors, a notable degree of similarity and shared dependence on flow discharge is observed among data in the literature. This prompts a crucial question about the extent of similarity in these curves for a particular species concerning ecohydraulic variables.

This work aims to address this query by considering literature data of HSIs measured in different worldwide locations and by various authors, all focused on the same fish species (i.e., the brown trout). The dependence of the HSI on particular ecohydraulic variables, such as water depth, velocity, temperature, and substrate are analysed by attributing the range of optimal values to the recommendations of the related authors. Histograms indicating the level of goodness of each range are then built and eventually smoothed by using fitting functions to reveal the universal characteristics of HSIs among worldwide rivers for the species being considered.  

How to cite: Padoan, F., Calvani, G., de Cesare, G., and Perona, P.: Assessing the Universality of Habitat Suitability Indexes (HSI) for brown trout (Salmo trutta L.) in Relation to Ecohydraulic Variables, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18264, https://doi.org/10.5194/egusphere-egu24-18264, 2024.

A.137
|
EGU24-16608
Sebastiano Piccolroaz, Ashkan Pilbala, Nicoletta Riccardi, Nina Benistati, Vanessa Modesto, Donatella Termini, Dario Manca, Augusto Benigni, Cristiano Corradini, Tommaso Lazzarin, Tommaso Moramarco, and Luigi Fraccarollo

Quantifying the effects of external climatic and anthropogenic stressors on aquatic ecosystems is an important task for scientific and management progress in the field of water resources. In this study, we propose an innovative use of biotic communities as real-time indicators, which offers a promising solution for directly quantifying the impact of these external stressors on aquatic ecosystems. Specifically, we investigated the influence of natural river floods on biotic communities using freshwater mussels (FMs) as reliable bioindicators. Using a well-established valvometry technique, we measured the valve-opening behaviour of FMs, considering both amplitude and frequency. The valve gap movement of the FMs was monitored by installing a magnet on one valve and a Hall effect sensor on the other valve and recording the magnetic field between the magnet and the sensor itself using an Arduino board, which changes according to the distance between the two valves. The recorded data was then analysed using the Continuous Wavelet Transform (CWT) analysis to study the time-dependent frequency of the signals. The experiments were carried out in a laboratory flume and in the River Paglia (Italy). The laboratory experiments were carried out with FMs in two configurations: freely moving or immobilised on vertical bars. The immobilised configuration was necessary for the field application to prevent the FRMs from packing against the downstream wall of the protection cage during floods. These experiments allowed us to verify that immobilised mussels show similar responses to abrupt increases in flow conditions as free mussels, but produce more consistent and interpretable signals than free mussels due to the reduced number of features resulting from movement constraints. We then analysed the response of thirteen immobilised mussels in real river conditions during a moderate flood on 31 March 2022.  The FMs in the field showed a rapid and significant change in valve gap frequency as the flood escalated, confirming the laboratory results. These results highlight the effectiveness of using FMs as bioindicators for assessing flood impacts on aquatic ecosystems, and emphasise the utility of CWT as a powerful signal processing tool for analysing valvometric time series. The study proposes the integration of FM valvometry and CWT for the development of operational real-time Biological Early Warning Systems (BEWS) aimed to monitor and protect aquatic ecosystems.

How to cite: Piccolroaz, S., Pilbala, A., Riccardi, N., Benistati, N., Modesto, V., Termini, D., Manca, D., Benigni, A., Corradini, C., Lazzarin, T., Moramarco, T., and Fraccarollo, L.: Using freshwater mussel valvometry data as a real-time biological warning system for aquatic ecosystems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16608, https://doi.org/10.5194/egusphere-egu24-16608, 2024.

A.138
|
EGU24-15124
|
ECS
Shun Hu and Qian Zhao

Overexploitation of water resources has led to severe ecological degradation and even desertification in many terminal wetlands in arid inland river basins, northwestern China. To restore the degraded vegetation ecosystem, ecological water conveyance projects (EWCPs) have become an important measure. Scientific assessment of the ecological stability of restored vegetation is of great importance for formulating reasonable ecological water management. Considering this, a systematic study was conducted in a typical terminal wetland of the Qingtu Lake Wetland (QLW) in Shiyang River Basin, northwestern China. The pixel-scale restored vegetation area (RVA) each year since the start of EWCP was extracted based on remotely sensed vegetation index. RVA increased dramatically in the first five years and became stable from 2016. The time lag of the response of RVA increase to ecological water conveyance was about 2 years. A bell-shaped function between RVA and groundwater depth was obtained based on the micro terrain of QLW via UAV. Five groundwater depth thresholds were then determined. The optimal groundwater depth in the hydrometric station was 2.91±0.09 m for the maximal RVA (17.08±3.25 km2). The optimal ecological water volume into Qingtu Lake was further estimated (the volume is 2224.4×104 m3) for the maximal RVA by a polynomial function between ecological water volume and groundwater depth. With the help of remotely sensed soil salinization and water surface, the vegetation restored during the first few years of EWCP in the southwest, west and north of QLW was found to degrade again due to the aggravation of soil salinization in these regions since 2019. Soil salinization was accelerated by the low groundwater depth with high mineralization and high evaporation capacity of climate without adequate inundation of ecological water by the unreasonable water allocation strategy. Under current simple and lax ecological water management in QLW, soil salinization will intensify and vegetation will further degrade. In other words, the ecological status of restored vegetation in QLW is unstable. Based on the optimal ecological water volume, even distribution of ecological water is helpful to maintain the stability of restored vegetation.

How to cite: Hu, S. and Zhao, Q.: The ecological stability of restored vegetation by ecological water conveyance project in a typical terminal wetland in an arid inland river basin, northwestern China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15124, https://doi.org/10.5194/egusphere-egu24-15124, 2024.

A.139
|
EGU24-8990
|
ECS
Neeraj Chauhan, Stefan Krause, Jaswant Singh, Amrit Pal Toor, and Alok Srivastava

The escalating levels of uranium in groundwater present a critical challenge to public health and environmental sustainability in the Malwa region of Punjab, India. This study addresses the dearth of understanding regarding uranium contamination by investigating its hydrogeochemical behavior in the hot, sub-tropical steppe, semi-arid Malwa region. Our research aims to unravel the controlling factors influencing uranium mobility and distribution in groundwater. Ion chromatography was employed for the comprehensive determination of cations (Na+, K+, Li+, Ba+) and anions (F-, Cl-, Br-, NO3-, SO42-, PO4-). Inductive-coupled plasma mass spectrometry was utilized for the quantification of heavy elements including strontium (Sr), cadmium (Cd), lead (Pb), uranium (U), aluminium (Al), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), cobalt (Co), zinc (Zn), arsenic (As), and selenium (Se) concentrations in groundwater samples. Results indicate alarming uranium levels ranging from 1.13 to 299.40 µg/L with mean of 54.03 µg/L. 73% to 92% of samples surpassing Bureau of Indian Standards (BIS) and World Health Organization (WHO) guidelines. Groundwater is primarily of Mg-HCO3 type which exhibited alkaline characteristics attributed to silicate weathering, ion exchange, and carbonate weathering in semi-arid conditions. Cluster analysis grouped uranium with nitrate, sodium and potassium, emphasizing their interconnected behavior. Spearman correlation analysis revealed a close association between uranium concentrations and various parameters including electrical conductivity, total dissolved solids (TDS), alkalinity, nitrate, sulfate, Na, and K. TDS, nitrate, and alkalinity exhibited high correlations with uranium which indicates that salt-induced competition among ions is the primary cause of uranium mobilization. This is evident in increased uranium levels with mixed water species (Mg-Cl, Na-HCO3). Furthermore, concerning levels of arsenic and selenium exceeding BIS and WHO limits underscore additional health concerns. This research underscores the urgent need for understanding and managing uranium contamination in the Malwa region. The broader implications for public health and environmental sustainability necessitate immediate attention and comprehensive remediation strategies.

How to cite: Chauhan, N., Krause, S., Singh, J., Toor, A. P., and Srivastava, A.: Assessing the Mitigation of Uranium and Heavy Toxic Elements with Physicochemical and Hydrogeochemical properties of groundwater in the Malwa Region of Punjab, India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8990, https://doi.org/10.5194/egusphere-egu24-8990, 2024.

A.140
|
EGU24-18591
|
ECS
Path flow of water, use of circular economy principle on water resources and biodiversity management in a port area using eDPSIR and causal network
(withdrawn)
Jérémie Solere, Valérie Borrell-Estupina, Roger Moussa, Clara Mainprize-Saurel, Jérémy Clément, Guillaume Papuga, and Arnaud Martin

Posters virtual: Fri, 19 Apr, 14:00–15:45 | vHall A

Display time: Fri, 19 Apr 08:30–Fri, 19 Apr 18:00
Chairpersons: Chengqi Zhang, Meng Zhu, Sara Bonetti
vA.19
|
EGU24-20738
|
Iongel Duran-Llacer, Francisco Zambrano, Víctor Gómez-Escalonilla Canales, Pedro Martínez Santos, Marcelo Aliagada Alvarado, Lien Rodríguez-López, Rebeca Martínez-Retureta, and José Luis Arumí

Drought is considered the main climate limitation that affects the hydrological cycle, agriculture, people, and ecosystems. Since 2010, central Chile has been experiencing an uninterrupted sequence of dry years that has been classified as a megadrought, which has conditioned major social problems. This problem can't only affect agriculture, people, and access to drinking water in Chilean basins, but it can also affect the ecological integrity of ecosystems, particularly those known as groundwater-dependent ecosystems (GDE). The main objective of this research is to examine the relationship between groundwater-dependent ecosystems and drought using satellite data in the Aconcagua basin in central Chile.

Standardized Precipitation Index (SPI), Standardized Evapotranspiration Index (SPEI), Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) were calculated to analyses relationship between groundwater-dependent ecosystem and drought. In addition, these parameters were analysed throughout the basin. To obtain and process these indicators between the years 2002 and 2022, the Google Earth Engine platform and the R environment were used. Subsequently, statistical analysis of the time series was performed, including Pearson correlation, Mann Kendall test, and Sen slope estimator. The results show that the SPI-SPEI at 12-24 months had a moderate correlation with the NDVI in much of the basin (>4) and high in the GDEs (>0.5). The slope of the Sen was more pronounced in the GDE zones, and the trend was decreasing with respect to the NDVI. LST and SPEI increased in the GDEs. In conclusion, the GDE zones were affected by drought processes, which demonstrates the need for sustainable management of these important ecosystems.

How to cite: Duran-Llacer, I., Zambrano, F., Gómez-Escalonilla Canales, V., Martínez Santos, P., Aliagada Alvarado, M., Rodríguez-López, L., Martínez-Retureta, R., and Arumí, J. L.: The response of Groundwater-Dependent Ecosystems to drought in central Chile, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20738, https://doi.org/10.5194/egusphere-egu24-20738, 2024.

vA.20
|
EGU24-1926
|
ECS
Revealing the response of evapotranspiration and water use efficiency to vegetation changes in different types of urban green spaces
(withdrawn)
Rui Shao
vA.21
|
EGU24-4869
|
ECS
|
Jan Kreibich, Gilad Bino, William Glamore, and Richard Kingsford

Wetlands, among the world’s most biodiverse and productive ecosystems, face severe threats from flow regime alterations, unsustainable water management, land-use conversion, increasingly exacerbated by climate change. Reduced connectivity between river channels and their floodplain habitats is often a consequence of subsequent drying, significantly degrading ecological health. We investigated the impacts of a century of river regulation and upstream water abstractions on the Lowbidgee Floodplain in semi-arid Australia - a nationally important wetland ecosystem on the lower Murrumbidgee River within the Murray-Darling Basin. This floodplain, which includes the indigenous-managed Gayini Wetlands and Yanga National Park, has a rich Aboriginal cultural heritage and supports a range of threatened and endangered native Australian species. We utilized Landsat and Sentinel satellite data to map wetland inundation patterns from 1988 to the present. Through the analysis of discharge data from the floodplain’s river gauges, we modelled the extent and frequency of wetland inundation under variable water availability scenarios, resulting from river regulation and climate change. Additionally, we evaluated the effects of altered flow and flood regimes on the health of flood-dependent vegetation, using remote sensing-derived vegetation indices such as the NDVI and Fractional Vegetation Cover (FVC). Our study aims to inform environmental flow management for large-scale river and wetland restoration efforts. It also provides the indigenous landowners, the Nari Nari Tribal Council, with crucial data to support their land and water management.

How to cite: Kreibich, J., Bino, G., Glamore, W., and Kingsford, R.: Satellite-Based Inundation Modelling for Large-Scale Wetland Restoration in Semi-Arid Australia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4869, https://doi.org/10.5194/egusphere-egu24-4869, 2024.